Motor fuel



-that promote their effectiveness.

" UNITED STATES PATIENT OFFICE" MOTOR. FUEL,

Pharis Miller, Elizabeth, N. J., minor to Standard Oil Development Company, a corporation r of Delaware No Drawing.

Application December 27, 1939. Serial No. su s:

' 9 Claims. (Cl. 44- 9) This invention relates to spark-ignition engine motor fuels in which secondary and tertiary aryl amines having oxygen-containing aliphatic group substituents are used as blending agents.

As is well known, the ordinary hydrocarbon base fuels require improvement in anti-knock value measured in terms of octane'number to meet demands for satisfactory performance in modern high-compression engines. Formerly, aromatic compounds such as benzol and aniline were found useful as blending agents but with the development of engines having higher compression ratios, more effective anti-knock agents have been sought. Although highly effective agents like tetraethyl lead were developed, it is desirable to use these in minimal amounts, hence, they are best used together with fuel ingredients I The aromatic blending agents hitherto proposed, in general, have been found unsatisfactory for supplementing the leaq-alkyl anti-knock agents, be-

cause many of these aromatic compounds show poor lead susceptibility, i. e., a tendency to decrease the effectiveness of the lead-alkyl agents. Further difficulties have arisen in adapting fuels for modern engines; one of these is due to uneven distribution of high anti-knock compone nts ina multi-cylinder engine when the anti-knock agent has a relatively high volatility, another has been a lack of lubricity in fuels supplied to injection-type engines, and still another is a need of eliminating corrosiveness and carbonaceous deposits.

The present invention has as an object th provision of motor fuels with blending agents that volatilize with higher boiling fractions of the. fuels, that enhance the anti-knock value of both clear and leaded fuels, and that contribute other desirable properties which may be ascribed to amino and ester, or similar oxygen-containing aliphatic groups, for the purpose of counteracting corrosiveness, improving oiliness, and reducing carbonaceous deposits.

Contrary to what would be expected of arcmatic compound containing amino groups and compounds containing ester groups, it has now been found that secondary and tertiary aromatic amines bearing an ester-type substitu'ent group, e. g. even a straight chain acetoxy radical, have meritorious octane blending values.

The N-alkylated aromatic amine esters combine virtues of the amino compounds and ofoxygenated aliphatic compounds analogous to esters and yet have exceptionally high anti-knock blending values 'as measured in comparison to the well recognized reference compound isooctane. These advantageous blending agents may be described as constituted of one or two benzene nuclei attached to a secondary or tertiary amino group with one or both of the hydrogens of the amino group replaced by an alkyl group, such as a methyl, ethyl, propyl, or butyl radical of straight and branched chain types, and substituted for hydrogen in another part of the benzene nuclei an aliphatic group containing oxygen linked to carbon as in an ester group. A typical example of these compounds is N-methyl ortho-methyl anthranilate having the formula:

ocm

NOB:

The secondary amino group may be replaced in this type of compound by a tertiary aminogroup. the location of the groups may be altered, and so may the alkyl radicals, as has been indicated, but preferably they are ortho to one another. Furthermore, other alkyl and other analogous oxygen-containing groups may be present as substituents in the aromatic nucleus as has been indicated.

The manufacture of N-alkyl anthranilates'canbe carried out readily by any of a number of known methods, which, in general, involve first the step of forming an anthranilic acid, e. g.

' starting with o-nitrotoluene, phthallc anhydride,

hypohalite to the N-alkyl anthranilic acid, which is finally esterified.

In the practice of this invention, a hydrocarbon motor fuel base stock, such as gasoline or a high flashpoint naphtha fuel obtained'by any of the known refining methods, is blended with any desired eflective proportion of the blending agent. Although smaller amounts of these agents give an appreciable improvement, to obtain a substantial improvement proportions of about 2% to 10% or more by volume should be used.

To cite an example which illustrates the effectiveness of the blending agents provided in acby this invention, it might be noted that these cordance with the present invention: N-methyl ortho-methyi anthranilate blended with a 65 octane number (A. S. T. M.) gasoline base as a reference fuel in a concentration of 5% by vol- .ume was tested with and without added tetraethyl lead (TEL) to obtain the following data':

Cone A. S. T. M. octane Octane blending volum'e Octane rating of blend value or agent percent fi in base Clear +1 cc. TEL Clear Leaded 5 cap 70.3 78.3 110 110 It is noteworthy from thes results-that the alkyl anthranilates have a very good efiect on the fuel even"'when the fuel contains the 1e agent, for many-relatively good anti-knock addition agents are known tohave poor lead suscep, tibility.-

Aliphatic esters of the N-alkylated anthranilic' acids to be used as blending agents should boil preferably in the boiling range of the hydrocan bon fuel base. Accordingly, since these agents maybe advantageously blended with safetyr-iuels ,or high flash-point injection engine fuels having boiling ranges within the approximate limits of 300 F. to 600 R, the ester and allryl radicals may be varied to some extent in size. Also. other aliphatic groups containing oxygen linked tocarbon atoms similar'to, the manner in estengroups may be used as substitutents oi whatzmay be regarded as the Nalkylated aromaticamine-compounds, for example, the oxygen=containlng aliphatic substltutent group may be constituted in;

aasaoeo I claim:

1. A motor fuel comprising a hydrocarbon fuel base adapted for spark-ignition engines blended with a substantial anti-knock improving amount of an N-alkylated aromatic amine containing in the aromatic nucleus an aliphatic substituent radical in which oxygen is linked to carbon as in an ester group, said amino boiling within the boiling range of said fuel base and being in minor proportion thereto.

2, A motor fuel comprising gasoline hydrocarbons blended with a minor proportion of an N- allgvlated anthranilate boiling in the range at the fuel base in suincient amount to substantially -mcrease the octane number of the fuel.

3. A motor fuel comprising a liquid hydrocarbon fuel base boiling in the range or 300 F. to 600. F. and an N=aihylated anthranilate boiling within the range of said fuel base blended in a minor amount which substantially improves the anti-knock value oi the'iuel. v

4. A -motor iuel comprising gasoline hydrocarbons improvedby an addition of a lead-alkyl anti-knock agent and an N-alkylated anthranilatein sumcient amount to increase the effectiveness of said lead-alkyl anti-knock agent,-sai'd anthr'anilate boiling withinthe boiling range of saidhydrocarbons and being in minor proportion thereto.

5. A motor fuel comprising gasoline hydrocarbons and at least 2% ct a secondary aromatic alkyl amine containing an oxygen-containing aliphaticsubstituent group in the aromatic nucleus,

the manner of methylene dioxy, acetyl, acetonyl,

acetamido, alkoxy and analogous functions.

In addition to the advantages which have been mentioned for the blending agents contemplated compounds have been observed to remain in solution with the hydrocarbon fuel at low temperatures; this being particularly true when the allphatic groups contain from 3 to 8 carbon atoms. The various compounds which have been mentioned may be used individually or-mixed with one another. 'Theyare very satisfactorily adapted for use in fuelswith other addition agents especially lead alkyl antirknock agents. In general,

- they maybe employed in a fuel together with any of the ordinary addition agents such as oxidation inhibitors, dyes, gum fluxes, color stabilizers, corrosion inhibitors, etc., which one may desire to employ.

As many changes could be made in iormulat ing the indicated compositions without departing from the scope or this invention, it is intended said aromatic alkyl amine boiling ,within the boiling range of said hydrocarbons and being in minor proportion thereto.

6. A motor iuel composition as described in claim 5, in which said aromatic alkyl amine is an phatic groups,-said amine boiling in the boiling proportion thereto.

that all matter contained in the foregoing description should be interpreted as illustrative and not in a limiting sense.

range of said hydrocarbons and 9. A motor fuel comprising gasoline hydrocarbons blended with from 2% to 10% by volume of N-methyi ortho-methyl anthranilate.

PHARIS MILLER.

being in a minor 

